ASTM E203-24
(Test Method)Standard Test Method for Water Using Volumetric Karl Fischer Titration
Standard Test Method for Water Using Volumetric Karl Fischer Titration
SIGNIFICANCE AND USE
4.1 Titration techniques using KF reagent are one of the most widely used for the determination of water.
4.2 Although the volumetric KF titration can determine low levels of water, it is generally accepted that coulometric KF titrations (see Test Method E1064) are more accurate for routine determination of very low levels of water. As a general rule, if samples routinely contain water concentrations of 500 mg/kg or less, the coulometric technique should be considered.
4.3 Applications can be subdivided into two sections: (1) organic and inorganic compounds, in which water may be determined directly, and (2) compounds, in which water cannot be determined directly, but in which interferences may be eliminated by suitable chemical reactions or modifications of the procedure. Further discussion of interferences is included in Section 5 and Appendix X2.
4.4 Water can be determined directly in the presence of the following types of compounds:
Organic Compounds
Acetals
Ethers
Acids (Note 1)
Halides
Acyl halides
Hydrocarbons (saturated and unsaturated)
Alcohols
Ketones, stable (Note 4)
Aldehydes, stable (Note 2)
Nitriles
Amides
Orthoesters
Amines, weak (Note 3)
Peroxides (hydro, dialkyl)
Anhydrides
Sulfides
Disulfides
Thiocyanates
Esters
Thioesters
Inorganic Compounds
Acids (Note 5)
Cupric oxide
Acid oxides (Note 6)
Desiccants
Aluminum oxides
Hydrazine sulfate
Anhydrides
Salts of organic and inorganic acids (Note 6)
Barium dioxide
Calcium carbonate
Note 1: Some acids, such as formic, acetic, and adipic acid, are slowly esterified. When using pyridine-free reagents, commercially available buffer solutions can be added to the sample prior to titration. With formic acid, it may be necessary to use methanol-free solvents and titrants (1).4
Note 2: Examples of stable aldehydes are formaldehyde, sugars, chloral, etc. Formaldehyde polymers cont...
SCOPE
1.1 This test method is intended as a general guide for the application of the volumetric Karl Fischer (KF) titration for determining free water and water of hydration in most solid or liquid organic and inorganic compounds. This test method is designed for use with automatic titration systems capable of determining the KF titration end point potentiometrically; however, a manual titration method for determining the end point visually is included as Appendix X1. Samples that are gaseous at room temperature are not covered (see Appendix X4). This test method covers the use of pyridine-free KF reagents for determining water by the volumetric titration. Determination of water using KF coulometric titration is not discussed. By proper choice of the sample size, KF reagent concentration and apparatus, this test method is suitable for measurement of water over a wide concentration range, that is, parts per million to pure water.
1.2 The values stated in SI units are to be regarded as standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific warnings are given in 3.1.
1.4 Review the current Safety Data Sheets (SDS) for detailed information concerning toxicity, first aid procedures, and safety precautions for chemicals used in this test procedure.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E203 − 24
Standard Test Method for
1
Water Using Volumetric Karl Fischer Titration
This standard is issued under the fixed designation E203; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 2. Referenced Documents
2.1 A list of existing ASTM Karl Fischer methods, their
1.1 This test method is intended as a general guide for the
applications to various products, and the sponsoring commit-
application of the volumetric Karl Fischer (KF) titration for
tees is given in Appendix X3.
determining free water and water of hydration in most solid or
2
liquid organic and inorganic compounds. This test method is
2.2 ASTM Standards:
designed for use with automatic titration systems capable of
D803 Test Methods for Testing Tall Oil
determining the KF titration end point potentiometrically;
D890 Test Method for Water in Liquid Pine Chemicals
however, a manual titration method for determining the end
D1123 Test Methods for Water in Engine Coolant Concen-
point visually is included as Appendix X1. Samples that are
trate by the Karl Fischer Reagent Method
gaseous at room temperature are not covered (see Appendix
D1193 Specification for Reagent Water
X4). This test method covers the use of pyridine-free KF
D1348 Test Methods for Moisture in Cellulose (Withdrawn
3
reagents for determining water by the volumetric titration.
2017)
Determination of water using KF coulometric titration is not
D1364 Test Method for Water in Volatile Solvents (Karl
discussed. By proper choice of the sample size, KF reagent
Fischer Reagent Titration Method)
concentration and apparatus, this test method is suitable for
D1533 Test Method for Water in Insulating Liquids by
measurement of water over a wide concentration range, that is,
Coulometric Karl Fischer Titration
parts per million to pure water.
D1568 Test Methods for Sampling and Chemical Analysis of
3
Alkylbenzene Sulfonates (Withdrawn 2023)
1.2 The values stated in SI units are to be regarded as
D1631 Test Method for Water in Phenol and Related Mate-
standard.
rials by the Iodine Reagent Method
1.3 This standard does not purport to address all of the
D2072 Test Method for Water in Fatty Nitrogen Compounds
safety concerns, if any, associated with its use. It is the
3
(Withdrawn 2007)
responsibility of the user of this standard to establish appro-
D2575 Methods of Testing Polymerized Fatty Acids (With-
priate safety, health, and environmental practices and deter-
3
drawn 2007)
mine the applicability of regulatory limitations prior to use.
D3277 Test Methods for Moisture Content of Oil-
Specific warnings are given in 3.1.
3
Impregnated Cellulosic Insulation (Withdrawn 2010)
1.4 Review the current Safety Data Sheets (SDS) for de-
D3401 Test Methods for Water in Halogenated Organic
tailed information concerning toxicity, first aid procedures, and
Solvents and Their Admixtures
safety precautions for chemicals used in this test procedure.
D4017 Test Method for Water in Paints and Paint Materials
1.5 This international standard was developed in accor- by Karl Fischer Method
D4672 Test Method for Polyurethane Raw Materials: Deter-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the mination of Water Content of Polyols
Development of International Standards, Guides and Recom- D4928 Test Method for Water in Crude Oils by Coulometric
mendations issued by the World Trade Organization Technical Karl Fischer Titration
Barriers to Trade (TBT) Committee. D5460 Test Method for Rubber Compounding Materials—
Water in Rubber Additives
1 2
This test method is under the jurisdiction of ASTM Committee D16 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Aromatic, Industrial, Specialty and Related Chemicals and is the direct responsi- contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
bility of Subcommittee D16.04 on Instrumental Analysis. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Jan. 1, 2024. Published January 2024. Originally the ASTM website.
3
approved in 1962 as E203 – 62 T. Last previous edition approved in 2023 as The last approved version of this historical standard is referenced on
E203 – 23. DOI: 10.1520/E0203-24. www.astm.org.
*A Summary of Changes section appears
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E203 − 23 E203 − 24
Standard Test Method for
1
Water Using Volumetric Karl Fischer Titration
This standard is issued under the fixed designation E203; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This test method is intended as a general guide for the application of the volumetric Karl Fischer (KF) titration for determining
free water and water of hydration in most solid or liquid organic and inorganic compounds. This test method is designed for use
with automatic titration systems capable of determining the KF titration end point potentiometrically; however, a manual titration
method for determining the end point visually is included as Appendix X1. Samples that are gaseous at room temperature are not
covered (see Appendix X4). This test method covers the use of both pyridine and pyridine-free KF reagents for determining water
by the volumetric titration. Determination of water using KF coulometric titration is not discussed. By proper choice of the sample
size, KF reagent concentration and apparatus, this test method is suitable for measurement of water over a wide concentration
range, that is, parts per million to pure water.
1.2 The values stated in SI units are to be regarded as standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. Specific warnings are given in 3.1 and 7.3.3.
1.4 Review the current Safety Data Sheets (SDS) for detailed information concerning toxicity, first aid procedures, and safety
precautions for chemicals used in this test procedure.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 A list of existing ASTM Karl Fischer methods, their applications to various products, and the sponsoring committees is given
in Appendix X3.
2
2.2 ASTM Standards:
D803 Test Methods for Testing Tall Oil
D890 Test Method for Water in Liquid Pine Chemicals
D1123 Test Methods for Water in Engine Coolant Concentrate by the Karl Fischer Reagent Method
1
This test method is under the jurisdiction of ASTM Committee D16 on Aromatic, Industrial, Specialty and Related Chemicals and is the direct responsibility of
Subcommittee D16.04 on Instrumental Analysis.
Current edition approved July 15, 2023Jan. 1, 2024. Published August 2023January 2024. Originally approved in 1962 as E203 – 62 T. Last previous edition approved
in 20162023 as E203 – 16.E203 – 23. DOI: 10.1520/E0203-23.10.1520/E0203-24.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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E203 − 24
D1193 Specification for Reagent Water
3
D1348 Test Methods for Moisture in Cellulose (Withdrawn 2017)
D1364 Test Method for Water in Volatile Solvents (Karl Fischer Reagent Titration Method)
D1533 Test Method for Water in Insulating Liquids by Coulometric Karl Fischer Titration
3
D1568 Test Methods for Sampling and Chemical Analysis of Alkylbenzene Sulfonates (Withdrawn 2023)
D1631 Test Method for Water in Phenol and Related Materials by the Iodine Reagent Method
3
D2072 Test Method for Water in Fatty Nitrogen Compounds (Withdrawn 2007)
3
D2575 Methods of Testing Polymerized Fatty Acids (Withdrawn 2007)
3
D3277 Test Methods for Moisture Content of Oil-Impregnated Cellulosic Insulation (Withdrawn 2010)
D3401 Test Methods for Water in Halogenated Organic Solvents and Their Admixtures
D4017 Test Me
...
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